Mini Actuators for Safety Critical Unmanned Aerial Vehicles Avionics
The present article details the development steps and experimental results obtained during the development of smart actuators used on mini unmanned aerial vehicles (UAV). The research effort is driven by the need of developing onboard health monitoring and diagnostics units for small size UAVs to improve their reliability. In the present all small UAVs use single string avionics systems with no built in redundancy, moreover the servo actuators onboard the airplane are often commercial off the shelf (COTS) hobby components with no reliability figures, limited performance guarantees and one directional communication using analog PWM signals. The development of new servo generation focused on solving the above issues. The proposed servo actuators use the existing mechanical gearboxes and housing of the COTS components, but their power electronics, motor control hardware and software components, sensors are custom designed to fit the needs of a higher demand. The actuators with their controlling microprocessors are capable of establishing two way communication via CAN and FlexRay protocol, suitable for safety critical applications, and self diagnostics features are also hosted onboard the actuators. The development challenges and experimental results in a hardware-in-the-loop (HIL) simulator are discussed in the paper.